diff --git a/staticlibs/native/bpf_headers/include/bpf/KernelVersion.h b/staticlibs/native/bpf_headers/include/bpf/KernelVersion.h
index e0e53a9..29a36e6 100644
--- a/staticlibs/native/bpf_headers/include/bpf/KernelVersion.h
+++ b/staticlibs/native/bpf_headers/include/bpf/KernelVersion.h
@@ -16,8 +16,7 @@
 
 #pragma once
 
-#include <stdlib.h>
-#include <string.h>
+#include <stdio.h>
 #include <sys/utsname.h>
 
 namespace android {
diff --git a/staticlibs/native/tcutils/Android.bp b/staticlibs/native/tcutils/Android.bp
index 88a2683..84a32ed 100644
--- a/staticlibs/native/tcutils/Android.bp
+++ b/staticlibs/native/tcutils/Android.bp
@@ -20,7 +20,7 @@
     name: "libtcutils",
     srcs: ["tcutils.cpp"],
     export_include_dirs: ["include"],
-    header_libs: ["bpf_syscall_wrappers"],
+    header_libs: ["bpf_headers"],
     shared_libs: [
         "liblog",
     ],
@@ -53,7 +53,7 @@
         "-Werror",
         "-Wno-error=unused-variable",
     ],
-    header_libs: ["bpf_syscall_wrappers"],
+    header_libs: ["bpf_headers"],
     static_libs: [
         "libgmock",
         "libtcutils",
diff --git a/staticlibs/native/tcutils/kernelversion.h b/staticlibs/native/tcutils/kernelversion.h
deleted file mode 100644
index 9aab31d..0000000
--- a/staticlibs/native/tcutils/kernelversion.h
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * Copyright (C) 2022 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-// -----------------------------------------------------------------------------
-// TODO - This should be replaced with BpfUtils in bpf_headers.
-// Currently, bpf_headers contains a bunch requirements it doesn't actually provide, such as a
-// non-ndk liblog version, and some version of libbase. libtcutils does not have access to either of
-// these, so I think this will have to wait until we figure out a way around this.
-//
-// In the mean time copying verbatim from:
-//   frameworks/libs/net/common/native/bpf_headers
-
-#pragma once
-
-#include <stdio.h>
-#include <sys/utsname.h>
-
-#define KVER(a, b, c) (((a) << 24) + ((b) << 16) + (c))
-
-namespace android {
-
-static inline unsigned uncachedKernelVersion() {
-  struct utsname buf;
-  if (uname(&buf)) return 0;
-
-  unsigned kver_major = 0;
-  unsigned kver_minor = 0;
-  unsigned kver_sub = 0;
-  (void)sscanf(buf.release, "%u.%u.%u", &kver_major, &kver_minor, &kver_sub);
-  return KVER(kver_major, kver_minor, kver_sub);
-}
-
-static unsigned kernelVersion() {
-  static unsigned kver = uncachedKernelVersion();
-  return kver;
-}
-
-static inline bool isAtLeastKernelVersion(unsigned major, unsigned minor,
-                                          unsigned sub) {
-  return kernelVersion() >= KVER(major, minor, sub);
-}
-
-} // namespace android
diff --git a/staticlibs/native/tcutils/tcutils.cpp b/staticlibs/native/tcutils/tcutils.cpp
index 4101885..37a7ec8 100644
--- a/staticlibs/native/tcutils/tcutils.cpp
+++ b/staticlibs/native/tcutils/tcutils.cpp
@@ -19,7 +19,7 @@
 #include "tcutils/tcutils.h"
 
 #include "logging.h"
-#include "kernelversion.h"
+#include "bpf/KernelVersion.h"
 #include "scopeguard.h"
 
 #include <arpa/inet.h>
@@ -504,7 +504,7 @@
     // shipped with Android S, so (for safety) let's limit ourselves to
     // >5.10, ie. 5.11+ as a guarantee we're on Android T+ and thus no
     // longer need this non-upstream compatibility logic
-    static bool is_pre_5_11_kernel = !isAtLeastKernelVersion(5, 11, 0);
+    static bool is_pre_5_11_kernel = !bpf::isAtLeastKernelVersion(5, 11, 0);
     if (is_pre_5_11_kernel)
       return false;
   }
diff --git a/staticlibs/native/tcutils/tests/tcutils_test.cpp b/staticlibs/native/tcutils/tests/tcutils_test.cpp
index 3a89696..53835d7 100644
--- a/staticlibs/native/tcutils/tests/tcutils_test.cpp
+++ b/staticlibs/native/tcutils/tests/tcutils_test.cpp
@@ -18,7 +18,7 @@
 
 #include <gtest/gtest.h>
 
-#include "kernelversion.h"
+#include "bpf/KernelVersion.h"
 #include <tcutils/tcutils.h>
 
 #include <BpfSyscallWrappers.h>
@@ -82,7 +82,7 @@
   // TODO: this should likely be in the tethering module, where using netd.h would be ok
   static constexpr char bpfProgPath[] =
       "/sys/fs/bpf/tethering/prog_offload_schedcls_tether_downstream6_ether";
-  const int errNOENT = isAtLeastKernelVersion(4, 19, 0) ? ENOENT : EINVAL;
+  const int errNOENT = bpf::isAtLeastKernelVersion(4, 19, 0) ? ENOENT : EINVAL;
 
   // static test values
   static constexpr bool ingress = true;
@@ -118,7 +118,7 @@
   ASSERT_LE(3, fd);
   close(fd);
 
-  const int errNOENT = isAtLeastKernelVersion(4, 19, 0) ? ENOENT : EINVAL;
+  const int errNOENT = bpf::isAtLeastKernelVersion(4, 19, 0) ? ENOENT : EINVAL;
 
   // static test values
   static constexpr unsigned rateInBytesPerSec =
diff --git a/staticlibs/tests/unit/src/com/android/testutils/HandlerUtilsTest.kt b/staticlibs/tests/unit/src/com/android/testutils/HandlerUtilsTest.kt
new file mode 100644
index 0000000..46a3588
--- /dev/null
+++ b/staticlibs/tests/unit/src/com/android/testutils/HandlerUtilsTest.kt
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.testutils
+
+import android.os.Handler
+import android.os.HandlerThread
+import kotlin.test.assertEquals
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+private const val ATTEMPTS = 50 // Causes testWaitForIdle to take about 150ms on aosp_crosshatch-eng
+private const val TIMEOUT_MS = 200
+
+@RunWith(JUnit4::class)
+class HandlerUtilsTest {
+    @Test
+    fun testWaitForIdle() {
+        val handlerThread = HandlerThread("testHandler").apply { start() }
+
+        // Tests that waitForIdle can be called many times without ill impact if the service is
+        // already idle.
+        repeat(ATTEMPTS) {
+            handlerThread.waitForIdle(TIMEOUT_MS)
+        }
+
+        // Tests that calling waitForIdle waits for messages to be processed. Use both an
+        // inline runnable that's instantiated at each loop run and a runnable that's instantiated
+        // once for all.
+        val tempRunnable = object : Runnable {
+            // Use StringBuilder preferentially to StringBuffer because StringBuilder is NOT
+            // thread-safe. It's part of the point that both runnables run on the same thread
+            // so if anything is wrong in that space it's better to opportunistically use a class
+            // where things might go wrong, even if there is no guarantee of failure.
+            var memory = StringBuilder()
+            override fun run() {
+                memory.append("b")
+            }
+        }
+        repeat(ATTEMPTS) { i ->
+            handlerThread.threadHandler.post { tempRunnable.memory.append("a"); }
+            handlerThread.threadHandler.post(tempRunnable)
+            handlerThread.waitForIdle(TIMEOUT_MS)
+            assertEquals(tempRunnable.memory.toString(), "ab".repeat(i + 1))
+        }
+    }
+
+    // Statistical test : even if visibleOnHandlerThread doesn't work this is likely to succeed,
+    // but it will be at least flaky.
+    @Test
+    fun testVisibleOnHandlerThread() {
+        val handlerThread = HandlerThread("testHandler").apply { start() }
+        val handler = Handler(handlerThread.looper)
+
+        repeat(ATTEMPTS) { attempt ->
+            var x = -10
+            visibleOnHandlerThread(handler) { x = attempt }
+            assertEquals(attempt, x)
+            handler.post { assertEquals(attempt, x) }
+        }
+    }
+}
diff --git a/staticlibs/testutils/devicetests/com/android/testutils/HandlerUtils.kt b/staticlibs/testutils/devicetests/com/android/testutils/HandlerUtils.kt
index 861f45e..6871349 100644
--- a/staticlibs/testutils/devicetests/com/android/testutils/HandlerUtils.kt
+++ b/staticlibs/testutils/devicetests/com/android/testutils/HandlerUtils.kt
@@ -21,9 +21,14 @@
 import android.os.ConditionVariable
 import android.os.Handler
 import android.os.HandlerThread
+import android.util.Log
+import com.android.testutils.FunctionalUtils.ThrowingRunnable
+import java.lang.Exception
 import java.util.concurrent.Executor
 import kotlin.test.fail
 
+private const val TAG = "HandlerUtils"
+
 /**
  * Block until the specified Handler or HandlerThread becomes idle, or until timeoutMs has passed.
  */
@@ -48,3 +53,28 @@
         fail("Executor did not become idle after ${timeoutMs}ms")
     }
 }
+
+/**
+ * Executes a block of code, making its side effects visible on the caller and the handler thread
+ *
+ * After this function returns, the side effects of the passed block of code are guaranteed to be
+ * observed both on the thread running the handler and on the thread running this method.
+ * To achieve this, this method runs the passed block on the handler and blocks this thread
+ * until it's executed, so keep in mind this method will block, (including, if the handler isn't
+ * running, blocking forever).
+ */
+fun visibleOnHandlerThread(handler: Handler, r: ThrowingRunnable) {
+    val cv = ConditionVariable()
+    handler.post {
+        try {
+            r.run()
+        } catch (exception: Exception) {
+            Log.e(TAG, "visibleOnHandlerThread caught exception", exception)
+        }
+        cv.open()
+    }
+    // After block() returns, the handler thread has seen the change (since it ran it)
+    // and this thread also has seen the change (since cv.open() happens-before cv.block()
+    // returns).
+    cv.block()
+}